Denmark accused of tinkering with wind turbine noise regulations

According to experts, noise calculations by EPA (Danish Environmental Protection Agency) are being manipulated to the detriment of windmill neighbours.

By Michael Rothenborg

The new noise regulations for wind turbines, as Environment Minister Ida Auken (SF) has just sent in public consultation, have been prepared on an inadequate basis: The calculations, which are the basis for the law gives too low a figure for wind turbine low frequency noise - and therefore allows that mills are closer to residential than what is scientifically sound.

So believes internationally recognized noise researchers.

"One might be tempted to believe that EPA manipulate noise calculations, so the expansion of the wind power grid can proceed almost unhindered," said Henrik Møller, Professor of Acoustics at Aalborg University.

Difficult to find qualified noise experts

It is extremely difficult to find qualified noise experts in Denmark, who will both speak and are not on the EPA consultant list.

But in Sweden, professor of occupational and environmental medicine, Kerstin Persson Waye, from Gothenburg University supports the Aalborg researchers:

"The Danish Environmental Protection Agency measurements of sound insulation is fundamentally wrong, and the data should be discarded," writes Persson Waye together with Aalborg researchers in the scientific journal, the Journal of Low Frequency Noise, Vibration and Active Control.

Aalborg researchers agree with EPA that the overall noise limit should be 20 decibels (dB) indoor.

But they believe that EPA has failed to make accurate measurements of sound insulation in typical Danish houses: The Agency itself recommends that the indoor noise should be measured at three points, including two where external noise is perceived most strongly - but that the Agency has not done.

In addition, the new noise rules will permit the limit of 20 dB to be exceeded in 33 percent of the worst insulated houses. It is a break with normal practice. For example, the dB limit only was allowed to exceed in 10 percent of the coastal houses as the fast ferry Aarhus-Kalundborg some years ago was asked to dampen the low frequency noise.

Measurements made with closed windows

Finally, according to researchers it is a problem that all control measurements of wind turbine noise are made with closed windows.

Also it is a break with normal practice, according to the rules applicable to factories and other sources of noise, where measurements are made with open windows, too.

"All EPA faults move in the same direction. This means, in our view that the turbines, according to the agency’s estimates will only exceed the limit of 20 dB, when in reality you have up to 30 dB in the worst isolated houses, "says Henrik Møller.

25-30 dB indoors feels for residents near wind turbines typically, as if there is a truck idling just outside the house.

Rules were not allowed to be tightened

Henrik Møller and his colleagues at Aalborg University has been trying to get EPA to include more scientific results in the assessment of low frequency noise, but has been rejected.

After the EPA last year was taken into glaring faults, especially the Radical Party and the Unity List demanded that Aalborg researchers were involved in further work on noise rules.

The then Environment Minister Karen Elleman (V) agreed, but it has been difficult for researchers and the EPA to have a constructive dialogue going, especially because the minister later pointed out that the new noise rules do not need tightening.

"If the premise is that the rules should not be a tightening, you need to calculate wrong. That we could not accept, "said Henrik Møller.

He is also concerned that the new environment minister in a press release states that Denmark is "leading the fight against low frequency noise from wind turbines."

"Many other countries have long had rules for low-frequency noise: Sweden, Holland, Germany, Poland, Japan. Where we stand out is that we are the only country where the authorities have decided that the limits of low frequency noise should not apply to wind turbines, such as happened in 2006 ', highlights Henrik Møller.

Environment Minister can not promise anything specific

Environment Minister Ida Auken states that Denmark is the first with binding rules - 'that they are mandatory, is something that lawyers pay very much attention to, because they can not be derogated in the real world."

She promises that she will deal with all consultation responses, but she will not promise anything specific to the Aalborg researchers.

"I can see that there is a technical disagreement, but EPA has done a thorough job and has also consulted outside experts. And now we've actually made a noise limit that is more stringent than those applicable to the industry - where a daytime limit is a 25 dB limit."

But the turbine limit of 20 dB is only tougher if EPA calculates the noise properly. The researchers believe that that has not happened?

"We have used the same calculations for this as for industrial companies."

The researchers highlight that they make actual measurements of noise from industry. In case of wind turbines the noise is just calculated - and for example only with the windows closed, not open.

"I will just look at this question during this hearing."

Can you deny that there in this area is a tendency for the government and parliament to allow benefits to the mill owners and not the neighbors - because the deployment of numerous large turbines is needed to meet Denmark's climate targets?

"Yes, I can refuse, because if doubt have to benefit turbines, we would not have made a noise limit, which the wind industry seems is too harsh," said Ida Auken.

The Unity List is not convinced

The chair for the Unity Lists Energy committee in the Danish Parliament, Per Clausen, is not convinced and will now discuss the matter with the Minister.

He recognizes that government and its supporting party is keen to speed up the deployment of wind turbines.

"But that does not mean that there should be different noise limits for the neighbors to the mills, than to the neighbors to, for example, industry and roads," emphasizes Per Clausen.